High power user equipment (HPUE) using coherently combined power amplifiers

Abstract

A user equipment (UE) includes a transmit chain that includes multiple radio frequency transmitters, multiple power amplifiers and a front end (FE) through which signals are transmitted. To achieve a high power UE solution, aspects of the disclosure selectively combine two or more power amplifier outputs based on an expected power output of the UE. To synchronously combine the outputs, an output feedback signal from a feedback receiver is used to adjust a delay and a phase of one or more signals associated with the power amplifiers.

What is claimed is: 
     
       1. A user equipment (UE), comprising:
 a first antenna; 
 a second antenna; 
 first switched combiner circuitry coupled to the first antenna via a radio frequency front end device, the radio frequency front end device comprising a first input to receive a first signal from the first switched combiner circuitry; 
 second switched combiner circuitry coupled to the second antenna via the radio frequency front end device, the radio frequency front end device comprising a second input to receive a second signal from the second switched combiner circuitry, each of the first and second switched combiner circuitry operable to combine signals from a first transmit chain and a second transmit chain; 
 a feedback receiver coupled to the first antenna and the second antenna via the radio frequency front end device, the feedback receiver coupled to an output of the radio frequency front end device and configured to receive an output of the combined signals from the first transmit chain and the second transmit chain; 
 a first power amplifier selectively coupled to the first switched combiner circuitry and the second switched combiner circuitry and operable to amplify a signal from the first transmit chain; 
 a second power amplifier selectively coupled to the first switched combiner circuitry and the second switched combiner circuitry, and operable to amplify the signal from the second transmit chain; and 
 a modem coupled to the first transmit chain and the second transmit chain, the modem including a delay and a phase control logic circuit coupled to the feedback receiver, the delay and the phase control logic circuit operable to adjust a phase and a delay on at least one of the signals from the first transmit chain and second transmit chain to synchronize the signals. 
 
     
     
       2. The user equipment (UE) of  claim 1 , further comprising a controller operable to couple the second power amplifier to the first switched combiner circuitry for transmission of the combined signals to the first antenna at a high power level, the controller further operable to couple the second power amplifier to the second antenna for transmission of the signal from the second transmit chain to the second antenna at a low power level relative to the high power level. 
     
     
       3. The user equipment (UE) of  claim 2 , in which the low power level corresponds to a Class-3 power amplifier, and the high power level corresponds to a Class-2 power amplifier. 
     
     
       4. The user equipment (UE) of  claim 2 , further comprising a first local oscillator for the first transmit chain and a second local oscillator for the second transmit chain, a first frequency of the first local oscillator is different from a second frequency of the second local oscillator for transmission of the signal from the second transmit chain to the second antenna at the low power level. 
     
     
       5. The user equipment (UE) of  claim 1 , further comprising a correlation device configured to receive a feedback output signal, the correlation device configured to perform cross correlation to adjust the delay and the phase on at least one of the signals from the first transmit chain and second transmit chain. 
     
     
       6. The user equipment (UE) of  claim 1 , further comprising control logic circuitry operable to disable the first power amplifier when the second power amplifier is coupled to the second antenna. 
     
     
       7. The user equipment (UE) of  claim 1 , further comprising control logic circuitry operable to disable the second power amplifier when the first power amplifier is coupled to the first antenna. 
     
     
       8. The user equipment (UE) of  claim 1 , in which the first power amplifier is further selectively coupled to the first antenna and the second antenna. 
     
     
       9. The user equipment (UE) of  claim 1 , in which the second power amplifier is further selectively coupled to the first antenna and the second antenna. 
     
     
       10. The user equipment (UE) of  claim 1 , further comprising a local oscillator shared by the first transmit chain and the second transmit chain. 
     
     
       11. The user equipment (UE) of  claim 1 , further comprising a first local oscillator for the first transmit chain and a second local oscillator for the second transmit chain, a first frequency and a first phase of the first local oscillator is substantially the same as a second frequency and a second phase of the second local oscillator to combine the signals from the first transmit chain and the second transmit chain. 
     
     
       12. The user equipment (UE) of  claim 1 , in which the first switched combiner circuitry and the second switched combiner circuitry are further operable to coherently combine the signals from the first transmit chain and the second transmit chain. 
     
     
       13. A method of combining within a user equipment (UE), comprising:
 combining, at a first switched combiner circuit or a second switched combiner circuit, amplified signals of a first transmit chain and a second transmit chain based at least in part on whether the first transmit chain and the second transmit chain are coupled to the first switched combiner circuit or the second switched combiner circuit, in which the amplified signals of the first transmit chain and the second transmit chain are received at a first power level; 
 transmitting a combined signal from the amplified signals of the first transmit chain and the second transmit chain over a first antenna or a second antenna at a second power level greater than the first power level based at least in part on whether the first transmit chain and the second transmit chain are coupled to the first switched combiner circuit or the second switched combiner circuit; 
 receiving a feedback signal; and 
 performing cross correlation to adjust a delay and a phase on at least one of the amplified signals from the first transmit chain and second transmit chain. 
 
     
     
       14. The method of  claim 13 , further comprising disabling a first power amplifier when a second power amplifier is coupled to the second antenna to transmit an amplified signal from the second transmit chain. 
     
     
       15. The method of  claim 14 , further comprising:
 bypassing the first switched combiner circuit and the second switched combiner circuit to transmit the amplified signal from the second transmit chain at the first power level. 
 
     
     
       16. The method of  claim 13 , further comprising disabling a second power amplifier when a first power amplifier is coupled to the first antenna to transmit an amplified signal from the first transmit chain. 
     
     
       17. The method of  claim 13 , further comprising:
 selectively coupling a first power amplifier to the first switched combiner circuit and the second switched combiner circuit; and 
 selectively coupling a second power amplifier to the first switched combiner circuit and the second switched combiner circuit. 
 
     
     
       18. The method of  claim 17 , further comprising:
 coupling the first power amplifier and the second power amplifier to the first switched combiner circuit; and 
 combining the amplified signals of the first transmit chain and the second transmit chain to generate the combined signal at the second power level. 
 
     
     
       19. The method of  claim 17 , further comprising:
 coupling the first power amplifier and the second power amplifier to the second switched combiner circuit; and 
 combining the amplified signals of the first transmit chain and the second transmit chain to generate the combined signal at the second power level. 
 
     
     
       20. The method of  claim 13 , further comprising:
 coupling a first power amplifier to the first antenna; and 
 bypassing the first switched combiner circuit and the second switched combiner circuit when transmission at the first power level is expected. 
 
     
     
       21. The method of  claim 13 , further comprising:
 coupling a second power amplifier to the second antenna; and 
 bypassing the first switched combiner circuit and the second switched combiner circuit to transmit an amplified signal from the second transmit chain at the first power level. 
 
     
     
       22. The method of  claim 13 , in which the combining comprises coherently combining and the combined signal comprises a coherently combined signal. 
     
     
       23. An apparatus for combining within a user equipment (UE), comprising:
 a first antenna; 
 a second antenna; 
 first and second means for combining signals from a first transmit chain and a second transmit chain, the first combining means coupled to the first antenna via a radio frequency front end device and the second combining means coupled to the second antenna via the radio frequency front end device, the radio frequency front end device comprising a first input to receive a first signal from the first combining means, and a second input to receive a second signal from the second combining means; 
 a feedback receiver coupled to the first antenna and the second antenna via the radio frequency front end device, the feedback receiver coupled to an output of the radio frequency front end device and configured to receive an output of the combined signals from the first transmit chain and the second transmit chain; 
 means for amplifying a first signal from the first transmit chain, the first amplifying means selectively coupled to the first combining means and the second combining means; 
 means for amplifying a second signal from the second transmit chain, the second amplifying means selectively coupled to the first combining means and the second combining means; and 
 means for adjusting a phase and a delay on at least one of the signals from the first transmit chain and second transmit chain to synchronize the signals, the means for adjusting coupled to the feedback receiver. 
 
     
     
       24. The apparatus of  claim 23 , in which the first and second means are for coherently combining the signals from the first transmit chain and the second transmit chain. 
     
     
       25. A non-transitory computer-readable storage medium having non-transitory program code recorded thereon, the program code comprising:
 program code to combine, at a first switched combiner circuit or a second switched combiner circuit, amplified signals of a first transmit chain and a second transmit chain based at least in part on whether the first transmit chain and the second transmit chain are coupled to the first switched combiner circuit or the second switched combiner circuit, in which the amplified signals of the first transmit chain and the second transmit chain are received at a first power level; 
 program code to transmit a combined signal from the amplified signals of the first transmit chain and the second transmit chain over a first antenna or a second antenna at a second power level greater than the first power level based at least in part on whether the first transmit chain and the second transmit chain are coupled to the first switched combiner circuit or the second switched combiner circuit; 
 program code to receive a feedback signal; and 
 program code to perform cross correlation to adjust a delay and a phase on at least one of the amplified signals from the first transmit chain and second transmit chain. 
 
     
     
       26. The non-transitory computer-readable storage medium of  claim 25 , in which the program code to combine comprises program code to coherently combine; and
 the program code to transmit comprises program code to transmit a coherently combined signal. 
 
     
     
       27. A user equipment (UE), comprising:
 a first antenna; 
 a second antenna; 
 first switched combiner circuitry coupled to the first antenna; 
 second switched combiner circuitry coupled to the second antenna, each of the first and second switched combiner circuitry operable to combine signals from a first transmit chain and a second transmit chain; 
 a feedback receiver coupled to the first antenna and the second antenna; 
 a modem coupled to the first transmit chain and the second transmit chain, the modem including a delay and a phase control logic circuit coupled to the feedback receiver, the delay and the phase control logic circuit operable to adjust a phase and a delay on at least one of the signals from the first transmit chain and second transmit chain to synchronize the signals; 
 a first power amplifier selectively coupled to the first switched combiner circuitry and the second switched combiner circuitry and operable to amplify a signal from the first transmit chain; and 
 a second power amplifier selectively coupled to the first switched combiner circuitry and the second switched combiner circuitry, and operable to amplify the signal from the second transmit chain.